Abstract
In this article, we demonstrated various Hermite–Hadamard and Fejér type inequalities for modified h-convex functions. We showed several inequalities for the products of two modified h-convex functions. New identities related to inequalities in various forms are also established for different values of the function. We believe that the approach presented in this paper will inspire more research in this area.
Keywords:
Hermite–Hadamard inequality; Fejér inequality; modified h-convex functions; super-additive functions MSC:
26D15; 26D07; 26A51
1. Introduction
Convex functions are different from other function classes in that they are widely used in the areas of mathematics, statistics, optimization theory, and applied sciences. It results from the fact that its specific and practical meaning has a geometric interpretation. It is also one of the fundamentals of inequality theory and has developed into the main motivating element behind a number of inequalities. Convex analysis in the field of inequality theory has proven it to be the most significant and successful use of this notion since the concept of a convex function is beneficial in many fields of mathematical analysis and statistics. With the use of this concept, a number of traditional and analytical inequalities have been established, especially those of the Hermite–Hadamard, Fejér, Hardy, Simpson, and Ostrowski types [1,2,3].
One of the fundamental theorems of inequality theory is the notion of a convex function as follows:
Definition 1.
On a non-empty interval I on the real line , define the real function κ. The function κ is said to be convex on I if inequality
holds for all and
The Hermite–Hadamard inequality, which is the significant component of the widespread use and great geometrical interpretation of convex functions, has attracted a lot of interest in fundamental mathematics. Due to its numerous applications, especially in the fields of numerical analysis, engineering, physical science, and chemistry, this inequality has attracted the interest of several researchers from around the world. Recent years have seen rapid development in the theory of inequality. Many inequalities can be obtained for convex functions; nevertheless, among those, Hermite–Hadamard’s inequality is one of the most widely as well as intensively studied results. It is worth reflecting on the fact that the theories of inequality and convexity are closely related to one another. The idea of inequality is more intriguing as a result of this reality. In recent years, several new extensions, generalizations, and definitions of novel convexity have been given, and parallel developments in the theory of convexity inequality, particularly integral inequalities theory, have been emphasized. The Hermite–Hadamard inequality is formally expressed as follows:
Let be a convex function on the interval I of real numbers, and
The inequality in (1) will hold in reverse directions if is a concave function. The Hermite–Hadamard inequality, which is based on geometry, gives an upper and lower estimate for the integral mean of any convex function defined on a closed and limited domain, which includes the endpoints and midpoint of the domain of the function. Due to the significance of this inequality, several variations of the Hermite–Hadamard inequality have been examined in the literature for various classes of convexity, including harmonically convex, exponentially convex, s-convex, h-convex, and co-ordinate convex functions [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19].
In [4], the definition of modified h-convexity and the Hermite–Hadamard inequality for the modified h-convex functions are shown as follows:
Definition 2.
Let be positive functions. Then κ is called a modified h-convex function if
Theorem 1.
Let be modified h-convex function on the interval with then we have
If is taken in (2), then the classical Hermite–Hadamard inequality is obtained.
The Hermite–Hadamard inequalities, also known as Hermie–Hadamard–Fejér inequalities (Fejér inequalities), or its weighted versions are the most well-known inequalities relating to the integral mean of a convex function
Theorem 2
([20]). Let be convex on I and let with Then the inequality
holds, where is non-negative and symmetric to .
We are discussing the Hermite–Hadamard inequality if is considered in (3). Hermite–Hadamard- and Fejér-type inequalities have received substantial study and application in the last several decades in the fields of numerical analysis, information theory, optimisation theory, special means theory, and approximation theory. Numerous papers and monographs have further information regarding those inequalities. For recent results and generalizations regarding Fejér inequality see [20,21,22,23,24,25].
Moreover, in [4], Noor et al. proved a Fejér inequality using the modified h-convex functions again.
Lemma 1
(See [4]). Let κ be modified h-convex function. Then
where
Definition 3
(See [18]). A function is said to be a super-additive function if
for all
Definition 4
(See [19]). Two functions and are said to be similarly ordered, if
for every
Theorem 3
(See [26]). Let be convex functions on Then
and
where
In this study, in the first part, the basic identities used in the theory of inequality are given. In addition, inequalities and results obtained in the literature related to modified h-convex functions are provided. Modified h-convex function properties and fundamental calculus principles are used in the second section to arrive at conclusions that pertain to both sides of the Hadamard and Fejér inequalities.
Using the characteristics of modified h-convex functions, our aim in this article is to produce novel inequalities. These inequalities are related to the integral of the product of two functions. Furthermore, for different values of the function, new identities related to inequalities in different forms are obtained.
2. Main Results
Theorem 4.
Let be a modified h-convex function on the interval with and is non-negative, integrable and symmetric with respect to then
where
Proof.
Since can be the modified h-convex function and is non-negative, integrable and symmetric with respect to we can obtain that
This completes the proof. □
Remark 1.
In Theorem 4,
- 1.
- If we take , then we have the right-hand side of the Fejér inequality,
- 2.
- If we choose and then we have the right-hand side of the Hermite–Hadamard inequality.
Corollary 1.
Let h be a super-additive function. Under the assumptions of Theorem 4, then we have the following inequalities:
Also if we take
Theorem 5.
Let be two modified h-convex functions such that κ and ϑ are similarly ordered functions. If then
Proof.
Since and are modified h-convex functions, then
By using the similarly ordered properties of and , we have
Integrating the above inequality with respect to we obtain the required result. □
Corollary 2.
In Theorem 5,
- 1.
- If we take , then we have
- 2.
- If we choose then
- 3.
- If we choose we obtain
Theorem 6.
Let κ and ϑ be two modified h-convex functions such that κ and ϑ are similarly ordered functions. If then we have
where
and
Proof.
Since and are modified h-convex functions, then we get
Using the Lemma 1 and , are similarly ordered functions, then
Integrating the above inequality with respect to we obtain the required result. □
Corollary 3.
In Theorem 6, if we choose then
where
In addition to the above inequality, if then
Remark 2.
From Theorems 5 and 6, we obtain the following identities:
Theorem 7.
Let κ and ϑ be two modified h-convex functions such that κ and ϑ are similarly ordered functions. Then we have the following inequality:
where
and
Proof.
From and are the modified h-convexity functions, then we can obtain
Again using the definition of modified h-convex function, we can obtain
In the inequality mentioned above, we obtain the preferred result by integrating both sides with regard to . □
Theorem 8.
Let κ be modified -convex function, ϑ be the modified -convex function and κ and ϑ similarly ordered functions. and then
where
and
Proof.
Since and are modified -convex and -convex functions, respectively, we obtain
for all Hence,
By integrating both sides with respect to over the interval we obtain the required result.
Since and are similarly ordered functions, we can write . Therefore, the second inequality follows easily. □
Remark 3.
In Theorem 8, if we take then we obtain the inequality (4).
Theorem 9.
Let κ be a modified -convex function and ϑ be a modified -convex function, κ and ϑ are similarly ordered functions. and then we have
where
Proof.
Let and be modified -convex and -convex functions, respectively. Then we obtain
Again, using the definition of modified -convex and -convex functions, we have
Integrating both sides of the above inequality over , we obtain
The proof is completed. □
Remark 4.
In Theorem 9, if we take then we obtain the inequality (5).
3. Conclusions
In this study, the properties of modified h-convex functions are investigated. By using the properties of modified h-convex functions, new integral inequalities of the Hermite–Hadamard and Fejér types, well known in the literature, are obtained. The properties of the modified h-convex functions are used in this study to encourage the development of numerous Hermite–Hadamard inequalities.
Author Contributions
Conceptualization, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; methodology, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; software, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; validation, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; formal analysis, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; investigation, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; resources, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; data curation, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; writing—original draft preparation, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; writing—review and editing, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; visualization, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; supervision, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; project administration, Ç.Y., L.-I.C., G.R., B.Y. and D.B.; funding acquisition, D.B. All authors have read and agreed to the published version of the manuscript.
Funding
This research received no external funding.
Data Availability Statement
Not applicable.
Conflicts of Interest
The authors declare no conflict of interest.
References
- Nasir, J.; Qaisar, S.; Butt, S.I.; Qayyum, A. Some Ostrowski type inequalities for mappings whose second derivatives are preinvex function via fractional integral operator. AIMS Math. 2022, 7, 3303–3320. [Google Scholar] [CrossRef]
- Butt, S.I.; Umar, M.; Rashid, S.; Akdemir, A.O.; Chu, Y.M. New Hermite–Jensen–Mercer-type inequalities via k-fractional integrals. Adv. Diff. Equ. 2020, 1, 635. [Google Scholar] [CrossRef]
- Srivastava, H.M.; Sahoo, S.K.; Mohammed, P.O.; Kodamasingh, B.; Nonlaopon, K.; Abualnaja, K.M. Interval valued Hadamard-Fejér and Pachpatte Type inequalities pertaining to a new fractional integral operator with exponential kernel. AIMS Math. 2022, 7, 15041–15063. [Google Scholar] [CrossRef]
- Noor, M.A.; Noor, K.I.; Awan, M.U. Hermite-Hadamard inequalities for modified h-convex functions. TJMM 2014, 6, 171–180. [Google Scholar]
- Varošanec, S. On h-convexity. J. Math. Anal. Appl. 2007, 326, 303–311. [Google Scholar] [CrossRef]
- Li, P.Y.; Yan, Q.; Chu, Y.M.; Mukhtar, S.; Waheed, S. On some fractional integral inequalities for generalized strongly modified h-convex function. AIMS Math. 2020, 5, 6620–6638. [Google Scholar] [CrossRef]
- Feng, B.; Ghafoor, M.; Chu, Y.M.; Qureshi, M.I.; Feng, X.; Yao, C.; Qiao, X. Hermite-Hadamard and Jensen’s type inequalities for modified (p,h)-convex functions. AIMS Math. 2020, 5, 6959–6971. [Google Scholar] [CrossRef]
- Wang, X.; Saleem, M.S.; Aslam, K.N.; Wu, X.; Zhou, T. On Caputo–Fabrizio Fractional Integral Inequalities of Hermite–Hadamard Type for Modified h-convex Functions. J. Math. 2020, 2020, 8829140. [Google Scholar] [CrossRef]
- Özdemir, M.E.; Gürbüz, M.; Yildiz, C. Inequalities for mappings whose second derivatives are quasi-convex or h-convex functions. Miskolc Math. Notes 2014, 15, 635–649. [Google Scholar] [CrossRef]
- Mitrinovic, D.S.; Pecaric, J.E.; Fink, A.M. Classical and New Inequalities in Analysis; Kluwer Academic Publishers: Dordrecht, The Netherlands, 1993. [Google Scholar]
- Zhao, T.; Saleem, M.S.; Nazeer, W.; Bashir, I.; Hussain, I. On generalized strongly modified h-convex functions. J. Inequalities Appl. 2020, 2020, 11. [Google Scholar] [CrossRef]
- Sarıkaya, M.Z.; Sağlam, A.; Yıldırım, H. On some Hadamard-type inequalities for h-convex functions. J. Math. Inequal 2008, 2, 335–341. [Google Scholar] [CrossRef]
- Zhao, D.; Zhao, G.; Ye, G.; Liu, W.; Dragomir, S.S. On Hermite–Hadamard-Type Inequalities for Coordinated h-convex Interval-Valued Functions. Mathematics 2021, 9, 2352. [Google Scholar] [CrossRef]
- Bombardelli, M.; Varošanec, S. Properties of convex functions related to the Hermite-Hadamard-Fejér inequalities. Comput. Math. Appl. 2009, 58, 1869–1877. [Google Scholar] [CrossRef]
- İşcan, İ. New refinements for integral and sum forms of Hölder inequality. J. Inequalities Appl. 2019, 2019, 304. [Google Scholar] [CrossRef]
- Kadakal, M.; İşcan, İ.; Kadakal, H.; Bekar, K. On improvements of some integral inequalities. Honam Math. J. 2021, 43, 441–452. [Google Scholar] [CrossRef]
- Xiao, Z.G.; Zhang, Z.H.; Wu, Y.D. On weight Hermite-Hadamard inequalities. App. Math. Comp. 2011, 218, 1147–1152. [Google Scholar] [CrossRef]
- Alzer, H. A superadditive property of Hadamard’s gamma function. Abh. Math. Semin. Univ. Hambg. 2009, 79, 11–23. [Google Scholar] [CrossRef]
- Skala, H.J. On the characterization of certain similarly ordered super-additive functions. Proc. Am. Math. Soc. 1998, 126, 1349–1353. [Google Scholar] [CrossRef]
- Fejér, L. Uberdie Fourierreihen, II. Math. Naturwiss Anz. Ungar. Akad. Wiss Hung. 1906, 24, 369–390. (In Hungarian) [Google Scholar]
- Sarikaya, M.Z. On new Hermite Hadamard Fejér type integral inequalities. Stud. Univ. Babes-Bolyai Math. 2015, 57, 377–386. [Google Scholar]
- Kalsoom, H.; Vivas-Cortez, M.; Amer Latif, M.; Ahmad, H. Weighted Midpoint Hermite-Hadamard-Fejér Type Inequalities in Fractional Calculus for Harmonically Convex Functions. Fractal Fract. 2021, 5, 252. [Google Scholar] [CrossRef]
- Khan, M.B.; Macías-Díaz, J.E.; Treanţă, S.; Soliman, M.S. Some Fejér-Type Inequalities for Generalized Interval-Valued Convex Functions. Mathematics 2022, 10, 3851. [Google Scholar] [CrossRef]
- Vivas-Cortez, M.; Kórus, P.; Napoles-Valdes, J.E. Some generalized Hermite–Hadamard–Fejér inequality for convex functions. Adv. Diff. Equa. 2021, 1, 1–11. [Google Scholar] [CrossRef]
- Set, E.; İşcan, İ.; Sarikaya, M.Z.; Özdemir, M.E. On new inequalities of Hermite–Hadamard–Fejér type for convex functions via fractional integrals. Appl. Math. Comput. 2015, 259, 875–881. [Google Scholar] [CrossRef]
- Pachpatte, B.G. On some inequalities for convex functions. RGMIA Res. Rep. Coll. 2003, 6, 1–9. [Google Scholar]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |
© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).